The logic behind retailers' aversion to collecting sales tax wasn't hard to understand: if given a choice between two retailers, one charging sales tax and one not, many consumers would probably choose the former.

Using a selection of specific criteria I’ll be gauging how some of the top US retailers handle on-site search.

The search tool is perhaps the most common way for shoppers to navigate an ecommerce site, so therefore its effectiveness is paramount in directing highly motivated visitors, who know exactly what they’re looking for, around your site.

One of the biggest barriers for customers about to use a checkout is forcing them to register their details first.

Presenting them with page after page of forms in which they need to fill out the most unnecessary of personal details is a quick way to send your customers to the exit, leaving many abandoned baskets and lowering your conversion.

For example, if I get a message from my Rolling Stones app then I’ll almost definitely open it up and see what Mick wants to tell me.

Similarly if I get a notification that H&M has a sale on then I’ll probably see what’s up for grabs.

Data from Urban Airship shows that push messages increase both engagement and retention by as much as 40% and 116% respectively (though it’s worth noting that the company makes money by selling its mobile marketing services).

Similarly, data gathered by Localytics from 28,000 apps found that users who enable push notifications have a nearly 3x higher retention rate compared to those who disable them.